摘要:
A storage tank leak detection and prevention system that detects a breach or leak in the interstitial space of a double-walled fuel storage tank in a service station environment. The interstitial space is placed under a vacuum using a submersible turbine pump that is also used to pump fuel to the fuel dispensers in the service station and therefore a separate vacuum generating source is not required. A sensing unit and/or tank monitor monitors the vacuum level in the interstitial space over time. If a significant vacuum level change occurs in the interstitial space after the interstitial space is placed under a vacuum level, a catastrophic leak detection alarm is generated. If a minor vacuum level change occurs in the interstitial space after the interstitial space is placed under a vacuum, a precision leak detection alarm is generated. Functional tests also ensure that the leak detection system is functioning properly.
摘要:
A carbon canister to adsorb hydrocarbons from a hydrocarbon air mixture in a UST system to prevent fugitive emissions due to overpressurization. The carbon canister has an inlet port at one end coupled to the UST system. An outlet port on the opposite end of the canister is connected to a flow-limiting orifice with a known calibrated flow rate that vents in a controlled fashion to the atmosphere. When UST pressure rises slightly above ambient pressure, fuel vapors and air from the UST system enters, via the inlet port, into the canister, where hydrocarbons are adsorbed onto the surface of the activated carbon. The cleansed air vents through the controlled flow outlet port to atmosphere, thereby preventing excessive positive pressure from occurring in the UST system. The activated carbon is purged of hydrocarbons by means of reverse air flow caused by negative UST pressures that occur during periods of ORVR vehicle refueling.
摘要:
A carbon canister to adsorb hydrocarbons from a hydrocarbon air mixture in a UST system to prevent fugitive emissions due to overpressurization. The carbon canister has an inlet port at one end coupled to the UST system. An outlet port on the opposite end of the canister is connected to a flow-limiting orifice with a known calibrated flow rate that vents in a controlled fashion to the atmosphere. When UST pressure rises slightly above ambient pressure, fuel vapors and air from the UST system enters, via the inlet port, into the canister, where hydrocarbons are adsorbed onto the surface of the activated carbon. The cleansed air vents through the controlled flow outlet port to atmosphere, thereby preventing excessive positive pressure from occurring in the UST system. The activated carbon is purged of hydrocarbons by means of reverse air flow caused by negative UST pressures that occur during periods of ORVR vehicle refueling.
摘要:
A carbon canister for use with a fuel storage system having a fuel storage tank and a vent line connected thereto. The carbon canister includes an inner container having a first end and a second end, an outer container having a first end and a second end, the outer container being disposed about an outer surface of the inner container such that the outer container and the inner container are concentric. A first end plate is disposed at the first end of the inner container and the first end of the outer container and a second end plate is disposed at the second end of the inner container and the second end of the outer container, such that a first volume is defined by the inner container, the outer container, the first end plate and the second end plate, and hydrocarbon adsorbing activated carbon disposed in the first volume. The vent line of the fuel storage tank is external to the carbon canister and the first volume of the carbon canister is in fluid communication with the fuel storage tank.
摘要:
A system and method for removing, compressing, and storing excess air and vapors from a fuel dispensing facility fuel storage containment system during periods of over-pressurization without venting or processing the excess air and vapors. The stored air and vapors are subsequently returned back to the containment system during periods of under-pressurization that typically occur diurnally during periods of high fueling activity. The system may be used to compliment an ORVR compatible dispensing system that typically encounters over-pressurization problems when low or no refueling activity is occurring.
摘要:
A carbon canister for use with a fuel storage system having a fuel storage tank and a vent line connected thereto. The carbon canister includes an inner container having a first end and a second end, an outer container having a first end and a second end, the outer container being disposed about an outer surface of the inner container such that the outer container and the inner container are concentric. A first end plate is disposed at the first end of the inner container and the first end of the outer container and a second end plate is disposed at the second end of the inner container and the second end of the outer container, such that a first volume is defined by the inner container, the outer container, the first end plate and the second end plate, and hydrocarbon adsorbing activated carbon disposed in the first volume. The vent line of the fuel storage tank is external to the carbon canister and the first volume of the carbon canister is in fluid communication with the fuel storage tank.
摘要:
A carbon canister to adsorb hydrocarbons from a hydrocarbon air mixture in a UST system to prevent fugitive emissions due to overpressurization. The carbon canister has an inlet port at one end coupled to the UST system. An outlet port on the opposite end of the canister is connected to a flow-limiting orifice with a known calibrated flow rate that vents in a controlled fashion to the atmosphere. When UST pressure rises slightly above ambient pressure, fuel vapors and air from the UST system enters, via the inlet port, into the canister, where hydrocarbons are adsorbed onto the surface of the activated carbon. The cleansed air vents through the controlled flow outlet port to atmosphere, thereby preventing excessive positive pressure from occurring in the UST system. The activated carbon is purged of hydrocarbons by means of reverse air flow caused by negative UST pressures that occur during periods of ORVR vehicle refueling.
摘要:
A method and apparatus for monitoring and determining fuel vapor recovery performance is disclosed. The dispensing of liquid fuel into a tank by a conventional gas pump nozzle naturally displaces a mixture of air and fuel ullage vapor in the tank. These displaced vapors may be recovered at the dispensing point nozzle by a vapor recovery system. A properly functioning vapor recovery system recovers approximately one unit volume of vapor for every unit volume of dispensed liquid fuel. The ratio of recovered vapor to dispensed fuel is termed the A/L ratio, which should ideally be approximately equal to one (1). The A/L ratio, and thus the proper functioning of the vapor recovery system, may be determined by measuring liquid fuel flow and return vapor flow (using a vapor flow sensor) on a nozzle-by-nozzle basis. The disclosed methods and apparatus provide for the determination of A/L ratios for individual nozzles using a reduced number of vapor flow sensors. The disclosed methods and apparatus also provide for the determination of fuel dispensing system vapor containment integrity, and the differentiation of true vapor recovery failures as opposed to false failures resulting from the refueling of vehicles provided with onboard vapor recovery systems.
摘要:
A method and apparatus for monitoring and determining fuel vapor recovery performance is disclosed. The dispensing of liquid fuel into a tank by a conventional gas pump nozzle naturally displaces a mixture of air and fuel ullage vapor in the tank. These displaced vapors may be recovered at the dispensing point nozzle by a vapor recovery system. A properly functioning vapor recovery system recovers approximately one unit volume of vapor for every unit volume of dispensed liquid fuel. The ratio of recovered vapor to dispensed fuel is termed the A/L ratio, which should ideally be approximately equal to one (1). The A/L ratio, and thus the proper functioning of the vapor recovery system, may be determined by measuring liquid fuel flow and return vapor flow (using a vapor flow sensor) on a nozzle-by-nozzle basis. The disclosed methods and apparatus provide for the determination of A/L ratios for individual nozzles using a reduced number of vapor flow sensors. The disclosed methods and apparatus also provide for the determination of fuel dispensing system vapor containment integrity, and the differentiation of true vapor recovery failures as opposed to false failures resulting from the refueling of vehicles provided with onboard vapor recovery systems.
摘要:
A system and method for calculating the flow rate of a dispensing point or flow capacity of a pump and fuel delivery system and determining if the dispensing point or fuel delivery system has a blockage and/or a performance problem if the calculated dispensing point flow rate is other than expected. The calculated dispensing flow rate is calculated by collecting fuel tank level data points for a dispensing point that fall within start and stop events of the dispensing event. The slope of a fitted line to the fuel tank level data points is used as the indication of the flow rate of the dispensing point. Different mathematical techniques may be used to improve the flow rate calculation to compensate for the minimum resolution of collecting fuel tank level data and the dead time included in the data of a dispensing transaction.